Our spring almanac 07.05.2010 – 13.05.2010

Astroclock sequence of Schools and Constellations
This is the 19th seven day post of our spring almanac and so begins the second sequence of the Basingstoke based Astroclock Junior and Primary School astronomical posts.

The Man Who Drives the Great Cart
The constellation of Bootes is very prominent now, with its bright star Arcturus becoming very noticeable. No wonder it has been associated with myth and folklore, as well as being associated with this time of the year. The Romans called Bootes the Herdsman of the Septemtriones, the seven oxen, which are represented by the seven stars of the Great Cart, known to us as the Plough. The ancient Sumerians called the constellation Riv-but-sane, the Man Who Drives the Great Cart, clearly identifying a similar image-pattern to the Romans. Bootes is also associated with the ploughing of the fields in spring.

Arcturus is the third brightest star in the night sky, after Sirius and Canopus. It is, however, fainter than the combined light of the two main components of Alpha Centauri, which are too close together for the eye to resolve as separate sources of light, making Arcturus appear to be the fourth brightest. It is the second brightest star visible from northern latitudes and the brightest star in the northern celestial hemisphere. The star is in the Local Interstellar Cloud. An easy way to find Arcturus is to follow the arc of the handle of the Plough. By continuing in this path, one can find Spica (α Virginis) as well—hence the maxim, “Arc to Arcturus, then speed on to Spica.”

Arcturus is so bright partly because it is relatively close to the Solar System, being a mere 34 light years in distance, or just over 200 trillion miles, and also because of its size. The diameter of Arcturus is about 25 times that of our Sun, being about 22 million miles across.

Arcturus means in ancient Greek ‘bear watcher’, as we have noted before in our Astrofact files, because of its relative position to the constellation of the Great Bear. So stories connecting the constellation Bootes with Ursa Major seem quite natural, and like Ursa Major Bootes is one of the oldest of the constellations people have identified over thousands of years.

Chinese astronomy
In Chinese astronomy, Arcturus is called Da Jiao (大角, Great Horn, Pinyin: Dàjiǎo), because it is the brightest star in the Chinese constellation called Jiao Xiu. Chinese constellations come from the way the ancient Chinese grouped the stars. They are very different from the modern IAU recognized constellations. This is due to the independent development of ancient Chinese astronomy.

Ancient Chinese skywatchers divided their night sky into 31 regions, namely the Three Enclosures (三垣 sān yuán) and Twenty-eight Mansions (二十八宿 èrshíbā xiù). The Three Enclosures occupy the area close to the North Celestial Pole. The stars in the Three Enclosures can be seen all year around.
The Twenty-eight Mansions occupy the zodiacal band. They can be considered as the equivalent to the 12 zodiacal constellations in the Western Astronomy. In contrast to Western astronomy, the Twenty-eight Mansions reflect the movement of the Moon in a lunar month rather than the Sun in a solar year.

Names of the Months
In this 7 day period we are in the month of May. The name for the month of May comes from the name of the Roman goddess of growth and increase, Maia. All the 12 months of the modern calendar year still have their Roman names, and the establishment of twelve months certainly echoes the lunar cycle over a solar year. So our modern calendar has lots of ancient lore about it, however modern everyday life appears to be.

One attempt to change the names of the months in Europe happened in France just after the French Revolution of 1789. The revolutionary idea was to institute a new calendar, beginning from the ‘first year of liberty’. This was the ‘Calendar of Reason’, introduced in 1792 or Year One. It had uniform months of 30 days each with the extra 5 or 6 days reserved for holidays called Virtue, Genius, Labour, Opinion and Recompense. The new months were named and organized as follows:

Vendemaire (vintage) September 22 – October 21

Brumaire (mist) October 22 – November 20

Frimaire (frost) November 21 – December 20

Nivose (snow) December 21 – January 19

Pluvoise (rain) January 20 – February 18

Ventose (wind) February 19 – March 20

Germinal (seedtime) March 21 – April 19

Floreal (blossom) April 20 – May 19
We will add images to the months below as we go through the rest of the year.
Prairial (meadow) May 20 – June 18
Messidor (harvest) June 19 – July 18
Thermidor (heat) July 19 – August 17
Fructidor (fruits) August18 – September 16

Changing the names of the months may have been revolutionary, but the author of these changes, Philippe-Francois Nazaire Fabre d’Eglantine, seems to have chosen a more traditional, poetic and natural set of images, seasonal images of weather, growth and agricultural labour.

Ascension Day
May 13 is Ascension Day. Ascension Day marks the last earthly appearance of Christ after his resurrection. Christians believe Christ ascended into heaven. It is celebrated 40 days after Easter.

All Saints Church in Fairfields 13.05.2010


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